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It may cause future warranty issues if the dealership documents that the car has a custom tune.
Although I understand and agree with the above statement, it is VERY dealer dependent. My 2013 F-150 Ecoboost had down pipes, exhaust, intake, hot and cold side piping, intercooler and custom tuning. One of the coolant lines to the turbo started leaking and the dealer changed it without issue, all the while staring at the stainless downpipes which were inches away. The wrong dealer would have denied the warranty claim. Its a crap shoot.
With that said, removing custom tuning is not a bad idea prior to dealer service. That way they can flash any updates without issue.
 
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Benchmark times for 2019 Ascent:
Install total time 4 minutes 22 seconds (includes saving stock file)
Change map once AP is installed, about a minute.
Uninstall 3 minutes 39 seconds.


COBB is focused on making products and tunes that deliver increased performance to customers, in a progression that makes sense based on R&D evaluation of components and data gathering. Based on our testing and analysis, we don't have plans to make a downpipe for the Ascent or tunes for them at this time. We are investigating a different engine related product which we feel has greater performance value, but I cannot speak further on that at this time.

-Mike @ COBB
@COBBtuning . Any further information about a performance upgrade? I have been waiting patiently. It's been a few months since my bumper guard and lights install. I'm considering a K&N air filter, did read through that thread (and watched youtube projectfarm video, highly recommend). But before I pull the trigger I'd love to hear a) if I should hold out for a COBB release? b) will a KN Air filter make any difference with my AP stage 1 91 octance?
 

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I think you’re grasping at straws hoping for a K&N filter to make a noticeable difference in acceleration or fuel economy on a turbocharged Subaru. As a guy that has modded a crap-ton of turbo Subarus over the years, I’d wait on something worth spending money on.
For a long time it was well known any tampering with Subaru’s OEM box and filter resulted in zero and even negative gains, and even worse. Only in very high HP applications with protunes were differences seen. Then specific OTS intake maps started coming out that we’re tuned for specific products and of course nothing beats a dyno ProTune.
Spend money on a ProTune if you’re seeking more than the base OTS map. That’s money spent that will actually result in more usable power.
 

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I think you’re grasping at straws hoping for a K&N filter to make a noticeable difference in acceleration or fuel economy on a turbocharged Subaru. As a guy that has modded a crap-ton of turbo Subarus over the years, I’d wait on something worth spending money on.
For a long time it was well known any tampering with Subaru’s OEM box and filter resulted in zero and even negative gains, and even worse. Only in very high HP applications with protunes were differences seen. Then specific OTS intake maps started coming out that we’re tuned for specific products and of course nothing beats a dyno ProTune.
Spend money on a ProTune if you’re seeking more than the base OTS map. That’s money spent that will actually result in more usable power.
The best tests so far were done by Jason at Engineering Explained, where he noted (on a NA vehicle) a very tiny gain in hp. I am of the opinion that the gain is within the margin that cannot be pinned on the filter change. One would need to do numerous consistent tests in the exact same conditions, to evaluate.

So, I too am of the opinion that it's not worth it to purchase a K&N filter with the goal of seeing improvements in acceleration, fuel economy or other performance metrics. Even if Jason's NA tests apply to a turbo (much less ours), the improvements were marginal.

Now, if you want to purchase one so you have a "one and done, wash it when it's dirty" filter, sure, fine. Remember to let it dry very well so it doesn't grow stuff inside that box when you put it back. Some people do that by keeping a stock filter handy to swap in for a day or two (then back into a bag and box until next time), and others simply do it when their car has a day or two downtime. Some people leave their filters outside to dry. Not a good idea during various seasons of the year, such as now, when they'd get covered by fine particulates (such as the pollen that coats my car every day, after being washed off a day or two before).

Spend money on a ProTune if you’re seeking more than the base OTS map. That’s money spent that will actually result in more usable power.
One word of caution. During testing on the Ascent, COBB hit the torque under load that causes CVT chain slip, then backed off their map a few percent to what ended up being a 21% increase in HP and torque. That's common knowledge. They've posted that here and/or on their site. A while back, I posted that I knew the info regarding the safety margin, and, since I've found that if you dig well enough through the internet, you'll find it, I will post it here. LuK programmed a 25% safety margin into the original torque/load band vs clamping pressure band programming (clamping pressure is a variable band, determined by torque and load parameters). When you get too close, you run the risk of chain slip when you request the edge of the safety band and a load parameter exceeds designs. When you exceed the parameters, you have a WRX that you're complaining about having a crappy CVT when in reality, the issue is that you Stage 2 tuned it beyond the safety margin programmed into the system. ;):cry:

I would not ever exceed COBB's map's power increases until someone figures out how to reprogram the TCM to move the clamping pressure band to accommodate more power. So, I suggest to choose a ProTuner who understands the limits of the current clamping pressure configuration of the Ascent's TR690.
 

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Keep in mind also that with OP’s 91oct, a 91 ProTune will not stress the power train as much as full blown 93.
A conservative 91 ProTune by a quality tuner would bring the car up to powerful but safe levels IMO, not a “ragged-edge balls-out” 93 ProTune by a hack, as it were.
 

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Keep in mind also that with OP’s 91oct, a 91 ProTune will not stress the power train as much as full blown 93.
A conservative 91 ProTune by a quality tuner would bring the car up to powerful but safe levels IMO, not a “ragged-edge balls-out” 93 ProTune by a hack, as it were.
Totally agree. I think the OP is heading the correct direction. I suspect others possibly are not (I already know of a couple people planning on a more aggressive tune than COBB's 93 tune), so I figured I'd address that for anyone else following along considering going beyond that.

I'm waiting with baited breath to see if MR Tuning and others figure out how to adjust the clamping pressure. Even our TR690's programming is nowhere near its torque limits.
 

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^^ Makes you wonder if the next '22 STI will come with a TR690. Not my style - I'd go for the 6MT again all day, but I very highly doubt Subaru could spin up a home-grown DCT out of thin air.
 

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^^ Makes you wonder if the next '22 STI will come with a TR690. Not my style - I'd go for the 6MT again all day, but I very highly doubt Subaru could spin up a home-grown DCT out of thin air.
I believe the rumor is that JDM version is coming with the TR690 as one of the transmission options. They've already used it some higher torque JDM STIs.
 

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I think you’re grasping at straws hoping for a K&N filter to make a noticeable difference in acceleration or fuel economy on a turbocharged Subaru. As a guy that has modded a crap-ton of turbo Subarus over the years, I’d wait on something worth spending money on.
For a long time it was well known any tampering with Subaru’s OEM box and filter resulted in zero and even negative gains, and even worse. Only in very high HP applications with protunes were differences seen. Then specific OTS intake maps started coming out that we’re tuned for specific products and of course nothing beats a dyno ProTune.
Spend money on a ProTune if you’re seeking more than the base OTS map. That’s money spent that will actually result in more usable power.
Sort of. I'm not opposed to attempting it at least. I understand it likely will not make a huge difference. But with the COBB stage 1 correction 93 tune including a nameless catback exhaust I thought it couldn't hurt. I would be curious how this would actually result in less HP or potentially damage anything. I can't see how or why? I will not be going down the pro-tune, stage 2, route. No

Now, if you want to purchase one so you have a "one and done, wash it when it's dirty" filter, sure, fine. Remember to let it dry very well so it doesn't grow stuff inside that box when you put it back. Some people do that by keeping a stock filter handy to swap in for a day or two (then back into a bag and box until next time), and others simply do it when their car has a day or two downtime. Some people leave their filters outside to dry. Not a good idea during various seasons of the year, such as now, when they'd get covered by fine particulates (such as the pollen that coats my car every day, after being washed off a day or two before).
And that's just the other side benefit. I really wouldn't mind taking the time to clean it properly. I'm actually thinking of having a WIX air filter in to be able to swap/rotate. Any offroading or camping trips the K&N would not be in there. If any of you guys have seen ProjectFarm on youtube (highly recommend, best channel) he does a great air filter comparison. It ex situ ie not in the engine bay. Conclusion is that K&N has the highest flow rate, lowest air resistance, and terrible small particle filtration. So this would not be great for anything dusty/dirty.
 

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Conclusion is that K&N has the highest flow rate, lowest air resistance, and terrible small particle filtration. So this would not be great for anything dusty/dirty.
Wow, thanks for that. I hadn't seen that. Good to know, especially for my adventures.
 

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@BroDoze isn't lying, @gmatt1000 . Take a look at the annals of NASIOC, if you want proof. It actually may be easier to search a smaller enthusiast Forum, such as LegacyGT.com, but the information you'll find will be the same. To put it very, very simply, it comes down to airflow variances caused by the filter and/or intake configuration that cannot be accounted for in an "off the shelf" manner with a "generic" tune.

Stick with the exact parameters that Cobb (or, for that matter, whatever other tuning house/device you're using) gives you with an off-the-shelf tune.

If you want more, a custom tune is the way to go: driveabilty, economy, and performance can all be improved noticeably when the tuner is able to work on the specific vehicle, specific modifications, using the gasoline you normally use. Yes, this last one gives folks a hard eyeroll until they talk to anyone who tried to get tuned at a highly regarded midwestern race garage after having filled their tank from a station just down the street with supposed Top-Tier "93-octane" - and ended up having their runs aborted and tuning day ruined because of excessive detonation....

----

Full disclosure:

I'm not trying to dissuade you from using an aftermarket filter.

I had a first-generation Perrin Short-Ram on my '05 LGT - I loved it simply because of the way it made the car sound, which, to me was half the fun (as, really, blitzing the car around-town here will net in a speeding ticket, very, very quickly). This intake with the factory bypass valve was highly entertaining, and with an aftermarket, even more-so. :) That said, I saw some pretty wacky things with the datalog (I also had a wideband A/F in that car, installed a couple of months later and just prior to getting the car custom-tuned the first time) in the time that I installed it prior to getting my car in to tune (you'll see this old thread on LGT.com where a question asked of actual data from a person supposedly with "no issues" nets in a lack of reply, because, well, they probably didn't have actual data: https://legacygt.com/forums/showthread.php/perrin-short-ram-intake-15782.html - you'll see that I was rather new to the game at the time, that was about 2 months after I got that car, and 2 months before I further modified it and sought tune; data from me? both of my old datalogging laptops are derelicts, but I'm sure the data is on them somewhere, if you want to pay for data recovery! ;)).

And towards the tune, two different - both highly-regarded - professional tuners worked on that car during the 7 years I had it, and both of them had to spend a bit of extra time on the dyno to compensate for that intake.

I actually had three filters which I cleaned, oiled, and rotated. Those bulbs weren't cheap.

So....

If you want to do it, do it.

But understand that Cobb's parameters are there for a reason. :)
 

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Discussion Starter · #292 ·
Hello, Question for Cobb, I am considering getting the Hood with scoop for my Ascent Touring (for looks). From prior posts, you are working on some updates. Would my getting the hood help, hinder or have no effect, if I install the hood and buy you updates? I will also have the Accessport. Thanks
 

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Anyone in the South Florida Area have a Cobb Access Port?
 

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I don’t know if this has been discussed but I’m thinking of using Torco additive to increase octane to 93 or above because there is no available 93 at my area. Any thoughts or recommendations? I’ve been eyeing the Cobb accessport for a while.
 

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^^ Just use the 87+ with 91octane. The ECU will advance timing as much as it can for 91octane. Even running 87 with the COBB AP is totally worth the entry fee.
I’ve used octane boosters in the past with mixed results. I’ll never screw around with them again.
 

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^^ Just use the 87+ with 91octane. The ECU will advance timing as much as it can for 91octane. Even running 87 with the COBB AP is totally worth the entry fee.
I’ve used octane boosters in the past with mixed results. I’ll never screw around with them again.
I think I might do that. There is 100 octane available I. My area but $9.20 a gallon...gulp.
 

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I think I might do that. There is 100 octane available I. My area but $9.20 a gallon...gulp.
Many 100 octane fuels are leaded, and not unleaded. Please double check before you unintentionally put leaded gasoline in your tank. Regardless, I am not sure the tune is designed for 100 octane, but @COBB Tuning is far far more qualified to answer that question, as well as to comment on the use of octane boosters to "make up the difference" between 87 or 91 and 93 octane.
 

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Installed my COBB 87+ map before the weekend and I love the results. My issue was the constant throttle input adjustment and non-linear acceleration/bogging down around 40-45 km/h (coming from a 2015 3.6R Outback). To the point I would not have kept the Ascent without a product like this to make it so much better. Why could Subaru not have made it like this from the factory? Now I'll start using Petro-Canada 94 Octane to see how much better it can get.
 

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Hello everyone!

Making up the difference with a good octane booster that raise the octane over 10points will be good and best monitored by reviewing DAM and pinging. Not all gas is the same and the mixing is not guaranteed.

In respect to the 100octane, the MON will be important, Again the best review will be the DAM and pinging running the 92 map. But remember the lead will kill the CAT over time.
 

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Torco works but it would get annoying to add it at each fill up.

I ran Torco for a bit when experimenting on my other Subaru, but switched to water methanol injection which is much much easier to deal with. I am sure you could run the 93 tune with water meth injection. But it is a bit of work to get up and running.
 
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